People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

Pancreatic Cancer Early Symptoms: Recognizing These Signs Of Silent Killer Could Save Your Life

Cancer is a scary subject, but pancreatic cancer is one of the most feared diagnoses. According to Mayo Clinic, this condition is one of the leading causes of cancer deaths; once it's discovered, it's already too late to remove the cancer, and outcomes for other treatments are poor.

There are two types of pancreatic cancer: exocrine pancreatic cancers and pancreatic neuroendocrine tumors (NETs). Both forms of pancreatic cancer show few symptoms initially, and unless detected in the early stages, they can be difficult to treat, according to the American Cancer Society.

The symptoms of exocrine pancreatic cancer include jaundice, stomach and back pain, weight loss and poor appetite, nausea and vomiting and blood clots. Jaundice is when the eyes and skin develop a yellow tone due to a buildup of bilirubin in the liver, according to the American Cancer Society.

A loss of appetite or sudden weight loss may be an early sign of pancreatic cancer.Pixabay.com

Pancreatic cancer causes this by not allowing the liver to excrete bilirubin, which normally leaves our body via our stool. The American Cancer Society says signs of jaundice include dark urine, light-colored stool and itchy skin.

Pain occurring in the stomach or back can be a sign of pancreatic cancer if cancer begins in either the body or tail of the pancreas. This causes these parts of the pancreas to grow, which can cause pain in the stomach. Additionally, the American Cancer Society says if the cancer spread to nerves around the pancreas, back pain may occur.

Nausea and vomiting could be the result of pancreatic cancer if a tumor presses against the stomach. This can block the stomach, making it difficult for food to make its way through, according to the American Cancer Society.

Another symptom of pancreatic cancer are blood clots, but more specifically in a large vein that can sometimes be found in the leg. The result is known as deep vein thrombosis (DVT) and is characterized by pain, swelling, redness and warmth in the leg, according to the American Cancer Society.

While exocrine pancreatic cancer has symptoms that can be fairly detectable, pancreatic neuroendocrine tumors are not as easy to detect. The American Cancer Society says these tumors are characterized by the substance they create in excess.

Glucagonomas tumors (glucose excess) can also increase your blood sugar, possibly leading to diabetes. Symptoms include feeling hungry and thirsty, urinating often, diarrhea, weight loss and malnutrition. A symptom that causes most patients with glucagonomas to see their doctor is a red rash called necrolytic migratory erythema, which can move from place to place on the skin, according to the American Cancer Society.

An Insulinoma tumor (insulin excess) does the exact opposite of glucagonomas tumors. It causes low blood sugar (hypoglycemia), resulting in weakness, confusion and sweating. The American Cancer Society says if your blood sugar becomes too low, you can pass out or possible go into a coma.

A VIPoma tumor (a vasoactive intestinal peptide excess) can cause worsening diarrhea, muscle cramps and feeling weak or tired. These kinds of tumors can cause problems with digesting food due to low levels of acid in the stomach, according to the American Cancer Society.

Additionally, other kinds of pancreatic neuroendocrine tumors include Somatostatinomas, PPomas, Carcinoid, and non-functioning neuroendocrine tumors. Symptoms for pancreatic cancers are dependent on where the cancer is growing; if the cancer is growing in your bones, your bones will be in pain. The American Cancer Society says if it’s in your lungs, shortness of breath can occur.